Abstract:

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The MgB2 PITs, prepared by filling Fe tubes with MgB2 as a core, were processed
through different number of passes at room temperature via Routes A, BA, C and BC. The
mechanical properties of the PITs were measured in terms of density and hardness. The extent of the
compaction was also studied through shear punch test. The shape of the compacts remains circular
even after four passes via Route C & BC. Higher density and hardness along with higher USS is
observed from the PITs of Route C compared to Route BC. The PITs processed through Route A
and Route BA did not show sufficient compaction to carryout the density measurements. Thus, the
current study shows that Route C is the optimal route; to attain good mechanical properties in
ECAE processed MgB2 PITs with Fe tube.

Abstract: In order to research the cold deformation work hardening characteristic of new type low carbon bainitic steel, this article studies the effect of different degrees of cold deformation (elongation and compression) and different tempering temperatures on microstructure and mechanical properties of 15SiMn2Mo low carbon beinaitic steel. The results showed that with the tempering temperature increasing after 10% pre-tension deformation, the tensile strength and yield strength of the test material increased first and then decreased, and reached its peak value at 300°C, roughly the same as the strength of hot-rolling and 300°C tempering. With the compression deformation degree rising, the hardness of test material increased and showed the test material has good work hardening performance. Streamline and "z" shape ferrite banding appeared in microstructure. With the tempering temperature increasing, the microstructure of compressed deformation steel recoveried and recrystallized, the tendency of ferrite along the streamline was weakened, the new refining granular phase was enhanced and uniformity of microstructure was improved. The microstructure refinement was significantly increased with the compressive deformation degree rising.

Abstract: High specific strength metals with high formability are paramount requirement for maximizing productivity of structural components, aircraft panels & engine components in Automotive & aerospace industry. The material must be suitably processed for better strength & more formability. The formability depends upon several factors one of which is grain size. Finer the grain size better is the formability. In the present study the influence of temperature of thermo-mechanical treatment (TMT) on the microstructure of titanium ally Titan 31 in order to identify suitable TMT to refine the grain size has been investigated.The material was subjected to hot rolling at different temperatures in the range 800°C -900°C. Subsequently the material was subjected to annealing as well as normalizing heat treatments. Grain size and hardness measurements were carried out to identify suitable TMT. The study revealed that rolling at 800°C followed by annealing at the same temperature resulted finer grain size and low hardness that are conducive for better formability.

Abstract: This study is focused on fabricating and characterizing iron (Fe) composites prepared by powder metallurgy route reinforced with varying weight of Yttria (Y2O3). Composites were prepared based on 5 wt. % to 15 wt. % of reinforcement powder with particle size ranging from 1-10µm. Pure Fe matrix composites were also prepared for comparison purpose. This paper will report the microstructure, bulk density and micro hardness values of the composites. Powder characterization and microstructures of the composites were examined using Scanning Electron Microscope (SEM) which indicated homogenous distribution of reinforcement particles in the metal matrix. Bulk density of the composites was calculated using standard Archimedean method showing decreasing values as the weight percentage of Y2O3 increases. Micro-hardness was measured using micro-Vickers hardness instrument. The data obtained shows that the Fe-Y2O3 composites samples possessed superior hardness value with the increasing quantity of reinforcement compared to the unreinforced Fe composite.

Abstract: Composites made from phenolic resin are filled with conductive filler mixtures containing copper powders, natural graphite powders and carbon fibers. They are fabricated by compression molding technique. The density, electrical conductivity and hardness of composite are analyzed to determine the influence of copper particle size on the physical, electrical and mechanical properties of composite. It is found that there is a marked dependence of the electrical conductivity and hardness on copper particle size. The hardness decreases with the decreasing of copper particle size. However the electrical conductivity increases with the decreasing of copper particle size. The decreasing of copper particle size from 75 µm to 48 µm promotes a considerable increase in electrical conductivity by about 427%. The increased continuous conductive metal networks could be the main reason for the increasing of electrical conductivity as copper particle size decreases. The results also show that composites containing copper particles of different sizes have the nearly same density.